Figure 2. Baseline and post-6-month mean values and standard deviations for the Yo-Yo Intermittent Recovery Test (YYIRT) and countermovement jump performance between groups and birthdate quartiles. *Pre-post significant differences at p < 0.05; ***Pre-post significant differences at p < 0.001; #Between-group differences at p < 0.05; $Between-group differences at p < 0.05. CON: control; BG: birthdate grouping; q1q2: birthdate between January and June; q3q4: birthdate between July and December.